I've expanded on this a bit further in the blog post: How to password-protect your website with Cloudflare Workers

Use this worker to password-protect whole websites or some areas/specific pages.

E.g. limit access to a staging version of a website you're building.

See https://cloudflareworkers.com/#f5d2cc53bd3d55486ddd14b1eb6e6c83:https://www.cloudflarestatus.com/

In this example, to see https://www.cloudflarestatus.com/ you need to pass basic authentication.

User name: demouser

Password: demopassword

Requirements:

• your website's DNS is managed by Cloudflare
• corresponding DNS record is proxied (orange cloud)

In order to protect your website with this worker you will need to deploy worker code and configure route mapping. There are multiple ways you can deploy workers, here are couple options for your consideration.

If you care about Infrastructure as Code, skip to Option #2.

Create a worker.

• Go to Cloudflare Dashboard / Account Home / Workers
• Create a Worker
• Paste the code
• Save and Deploy

Configure route mapping.

• Go to Account Home / Domain / Workers
• Add route
• Provide route, e.g. example.com/protected/*
• Select worker
• Save

You're set! If you open example.com/protected/anything now it will prompt you to enter password.

Wrangler is a tool built by Cloudflare to develop, test and deploy workers code. For more thorough overview, check documentation.

First you need to collect some information from your CF account.

• Account ID.
  • Account Home / Domain / Overview tab / API section / Account ID
• Zone ID.
  • Account Home / Domain / Overview tab / API section / Zone ID
• API token.
  • Account Home / Domain / Overview tab / API section / Get API Token
  • Create Token
  • Start with Template
  • Select the Edit Cloudflare Workers template
  • Continue to Summary
  • Create Token

Install Wrangler. npm install -g @cloudflare/wrangler

Create Wrangler config. wrangler init --type javascript

Update Wrangler config. Example:

name = "cf-worker-basic-http-auth"
type = "javascript"
account_id = "<YOUR ACCOUNT ID>"
zone_id = "<YOUR ZONE ID>"
route = "example.com/protected/*"

Configure API token. wrangler config

Deploy worker. wrangler publish

see CONTRIBUTING.md